Thermomechanical Fluid-Structure Interaction in

Supersonic Flows: Experiments and Simulation

Katharina Martin, Stefanie Reese, IFAM, RWTH Aachen University

Dennis Daub, Burkard Esser, Ali Gülhan, AS-HYP, DLR Köln

Motivation

2

Aerothermal

Heating

Structural

Deformation

Why study thermomechanical FSI?

Motivation

Ariane 5 flight 517

Buckling of nozzle cooling

channels

3Stahlkocher - CC BY-SA 3.0

Motivation

4

Metallic thermal protection for reusable launchers

SpaceX - CC BY-NC 2.0

5

Motivation

NASA

Buckling of supersonic aircraft surface panels

Motivation

Dennis Daub

Joint experimental and numerical study of fluid-structure

coupled buckling problems using a generic configuration

Overview

Supersonic Fluid-Structure

Interaction in SFB TRR 40

• Turbulent SWBLI loads (D4 + D6 FP. 1/2)

• Flutter + Turbulent SWBLI (D6 FP. 3)

• Thermal buckling including plastic behavior

(D10 + D6 FP. 3)

8

Modelling / Simulation

9

Effect of buckling on the flow

panel mount

shockexpansion region

Ma = 7.7

nose shock

Main effects under

investigation

• Buckling with high amplitudes

• Plastic deformation

• Interaction of deformation

with flow field → strong

localized heating

α = 20°

Coupling tool IFLS, TU Braunschweig

Quasi-stationary process: fluid and structure

Equilibrium iteration method: Dirichlet-Neumann iteration

Transfer between grids: Lagrange multiplier

[Niesner, 2009; Haupt, 2009]

fluid

computation

fluid grid

transfer of

state quantities

solid grid

transfer of

state quantities

mechanical solid

computation

thermal solid

computation

Fluid-structure interaction (FSI)

10

• DLR Tau solver; laminar flow; ideal gas γ = 1.451

• Hybrid mesh, structured layers on the wall

• Mesh deforms as panel surface deforms

Fluid computation

Ma∞ = 7.7

p∞ = 50.3 Pa

T∞ = 477 K

α = 20°

freestream

viscous wallT(t0) = 300K

11

Material:

• panel and frame: Incoloy 800 HT

• isolation: Schupp Ultra Board 1850/500

• support plate: copper

Material model:

• mechanical: viscoplastic with nonlinear isotropic hardening + thermal expansion

• thermal: heat flux (Fourier) and radiation

Structural Computation

200 mm

12

100 mm

197 mmr = 45 mm

33 mm

17.5 mm

10 mm

35 mm

51.5 mm

55 mm 33 mm

nose not

modelled

panel

[Martin et al., 2018]

Mechanical boundary condition:

• bottom: circular fixation

• top: pressure p from fluid simulation

• symmetrical BC at y = 0

Boundary Conditions (BC)

T = 300K

13

q,p

nose not

modelled

Thermal boundary condition:

• bottom: temperature T = 300K

• top: heat flux q from fluid simulation

• cavity radiation between panel and

isolation / radiation on top surface

[Martin et al., 2018]

Material model for panel

14

• Viscoplastic material model with

– nonlinear isotropic hardening

– thermal expansion

– temperature dependent material parameters

• implemented in an Abaqus UMAT

• modified for a plane stress state in order to also use it

for shell elements

• thermo-dynamically consistent

• large deformations[Martin et al., 2019]

• Temperature range: 20°C – 1000°C

• loading rate: 0.5mm/min; 1mm/min

Material tests for Incoloy 800 HT

15

[Martin et al., 2018]

Arc-heated Wind Tunnel L3K

Ma∞ = 7.7

p∞ = 50.3 Pa

T∞ = 477 K

v∞ = 3756 m/s 16

[Daub, 2020]

Wind Tunnel Run

17

Instrumentation

Digital Image Correlation (DIC)

18

Infrared Thermography (IR)

Digital Image Correlation (DIC)

Validation (DIC)

20

Deformation

Validation (IR)

22

Surface Temperature

Reference Sensor Positions

FLOW

Panel (200x200)

front (50/0)

left (100/50)

center (100/0)

rear (150/0)

x

y

left

center rearfront

Comparison of Displacement Exp/Sim

25

Comparison at the center of the panel Comparison at four position of the panel

Comparison of Temperature Exp/Sim

26

Comparison at the center of the panel Comparison at four positions of the panel

Comparison Exp/Sim

27Comparison of displacement:

sim (left); exp (right)

Comparison of temperature:

sim (left); exp (right)

Discussion

28

More than 200 K

difference between rigid

and buckled case

Discussion

29

Influence of wall temperature on buckling shape

Conclusion

Interdisciplinary study of FSI in supersonic flow

• Fluid-Structure coupled simulations

• Modelling of plastic deformation

• Validation experiments with time-resolved full-field

instrumentation

Obtained good agreement between simulation and experiments

• Strong localized (FSI driven) heating

• Significant plastic deformation

30

Thank you

31

Financial support by the Deutsche Forschungsgemeinschaft (DFG) for the

SFB TRR 40 is gratefully acknowledged.